This is the second of a two part post by Geoff Russell. Part I sketched the quantitative features of the global fire regime, biomass flows, while this part looks primarily at Africa.

Boverty was defined in the previous post as the human impact of too many bovines overwhelming the local biosphere’s ability to feed them … the bovines are usually cattle and more than a few African countries have boverty induced poverty. Their livestock is a millstone around their necks and helping to keep them poor.

Western aid organisations, particularly those run by BBQ obsessed Australians, seem dominated by people haven’t woken up to the simple fact that the foods they grew up on when the planet had half its present population haven’t been sustainable globally for a very long time. Even in Australia, with its vast landmass and small human population, the production of these foods has driven and continues to drive water shortages, environmental degradation and biodiversity loss. Advocacy of such foods in Africa will benefit few and damage prospects of long term food security.

African reforestation

As outlined in the Part I, many grasslands on the planet are not the product of natural forces, but were cleared by people and kept as grasslands for livestock grazing by annual or occasional conflagrations. This is global burning on a massive scale as shown in the NASA firemaps presented in Part I. The continent with the most deliberate human burning is Africa. Over 200 million hectares and 2 billion tonnes of dry matter are burned annually in deliberately lit fires. Almost all of these fires are set by livestock herders to stop grasslands becoming forests. By comparison, burning by shifting cultivators for crops covered an area about 10 percent of this size. A recent study in Nature gives an idea of what could happen if the burning stopped. The reforestation potential is massive.

Consider the above image from the Nature article. The vertically hatched area has an average rainfall over 780mm and would, according to Sankaran and the large number of other authors, revert to some kind of forest if given half a chance. Its status as savanna is anthropogenic and not a product of natural attributes like soil type and climate.

How long can such regrowth go on adding carbon in the form of forests? Most additional carbon would be added during the first 3 decades but forests can go on adding smaller amounts for centuries. It’s worth noting that fire is probably always a suppressor of biomass production. The frequent claim that fire helps regeneration, making it some kind of friend of biodiversity, can be true but is highly misleading. I intend to do a post on this sometime in the future. But despite some plants benefitting from fire, the general impact is to reduce biomass production. Measurements under 2 rainfall regimes and 4 soil types in Africa always recorded higher biomass production in areas not burned.

One way of measuring a country’s fire intensity is to consider the ratio of biomass burned to biomass appropriated. We saw in Part I that Australia burns about 40 percent of what it appropriates. This ratio is the same as in South East Asia, but much higher than the 1 percent of Western Europe.

Both burn ratios pale beside the staggering 150 percent of sub-Saharan Africa where far more is burned than is otherwise appropriated. This is a stunning number. Corey Bradshaw recently wrote a piece on his blog where he summarised a recent paper on Australia’s mammal extinction crisis. His bottom line summary was that we should “Stop burning the shit out of our forests“. In sub-Saharan Africa, they are burning 12 times more biomass from an area 6 times bigger than the 37 million hectares we burn each year. If we are doing as Corey says, then what are the Africans doing? And for what? They reap far less than they burn.

Climate Change

How will global warming compound or alleviate Africa’s problems? The most critical impacts will be changes in rainfall regimes.

A warmer world is a wetter world but it is the timing and distribution of water that matters more than the absolute amount. This is as true for Africa as anywhere else. Perhaps the Sahara will gain water in a changing climate and return to its rather wetter state of 5000 years ago. Perhaps rainfall will be less regular but more intense, leading to more topsoil erosion and magnifying cattle impacts.

African Boverty

Africa is about 4 times the size of Australia but has 260 million cattle compared to our 28 million. On average the cattle are smaller with an average carcase weight of 150kg compared to 250kg in Australia. By now you may have predicted what so astonished me and drove the preparation of this post. The areas doing so much of the burning are precisely the ones with the most cattle and the most chronically hungry people. For example, Ethiopia and Sudan have 43 million and 41 million cattle respectively. In Ethiopia 80 million people eat 11 million tonnes of food while those 43 million cattle and assorted other livestock graze 80 million tonnes and are fed a further 20 million tonnes as feed. All these figures are DM (dry matter) numbers. Sudan burns over 30 percent of its entire annual vegetation growth … and this is 30 percent averaged over the entire country. Consider what this means. Australia burns huge areas, but averaged over the entire country the burn rate is less than 5 percent.

Cattle don’t bring food security

Proving that cattle cause starvation is tough, but demonstrating that cattle don’t protect people from food insecurity is trivially easy. It’s in the numbers.

This plot of per capita cattle ratios and undernourishment proportions shows pretty clearly that livestock are not effective in protecting people from hunger. Compare the food security of Nigeria, famously the happiest country on the planet which feeds 154 million people, with an undernourishment rate of 8 percent with Ethiopia, Sudan, Chad and Botswana. The latter have some of the worst poverty and chronic undernourishment on the planet while swimming in cattle and burning the shit out of their country every year. All the countries to the right of the 0.3 cattle per capita vertical line have more cattle per head of human population than the US. Allowing for the difference in cattle size we should really shift this line to about the 0.5 point. So Niger, Chad, Sudan and such have more cattle than the famously obese hamburger munching US. But still they starve. Does it look like more cattle will fix anything?

Nigeria’s submission to the IPCC states “Much of the savanna is a by-product of centuries of devastation by man and fire“. The author has a clear understanding of the problem and it looks as if some pretty effective steps have been taken because Nigeria’s biomass burning level is now just a tenth of Sudan’s. If you look at a high resolution version of the fire map from Part I of this post, you can see that Nigeria’s fires are fewer than those in the rest of that burning band. Nigeria feeds a population half the size of the population of the US but has only 10 percent of the land. Nigeria isn’t quite self sufficient in food, importing about 5 million tonnes of cereals to supplement the 25 million tonnes of cereals and 85 million tonnes of root vegetables it produces annually.

Root vegetables are probably the most efficient food crop per hectare of any on the planet. During some of the BNC discussion of Part I of this post, the subject of Polyface farm came up. Michael Pollan and Tim Flannery have both written flatteringly about this US farm. It is, to their minds, organic eco-friendly livestock production at its best. I did an analysis of Flannery’s vision for Quarterly Essay and will post a version of it on BNC at some time, but let me digress briefly on the production figures from Polyface which so astonished Tim Flannery in Now or Never, his Quarterly Essay. Polyface produces an annual combined total of 45 tonnes of various meats, plus some eggs from 60 hectares. The figures are probably carcase figures, so will be somewhat higher than the amount actually consumed.

An average Australian potato farmer would get some 2160 tonnes from 60 hectares, and the global average cereal productivity is well over 2 tonnes per hectare with many countries getting 3 or more times this yield. Most rice growers would get 400 to 600 tonnes from 60 hectares. Grow almonds on 60 hectares and you would get double the amount of protein without the pain and suffering of slaughter days at Polyface or the subsequent bowel cancer cases due to the red meat. And just to forestall the usual claims from US readers about grass fed meat being healthy and that all the many meat health issues are really just a result of grain feeding, I need to point out that most locally consumed red meat in Australia is grass fed, but we are generally top of the global table in bowel cancer rates. The causal chain from red meat to bowel cancer is now pretty well nailed down and has nothing to do with what the animals eat.

But returning to Nigeria. The Nigerians know about root vegetables, so next time you watch those brilliant Nigerian track athletes, the ones with the huge shoulders, just think of them as children … the odds are that they grew up on yams and other root vegetables!

Animal products provide less than 3 percent of Nigeria’s food calories. That 3 percent of animal products will more than likely be largely appropriated by the wealthy, the overseas oil consultants, and the tourists. Make no mistake, Nigeria is a desperately poor country with many serious public health issues, but its food production successes are remarkable given its tiny land area, its massive population, its history of burning, and the dominance of ignorant meat centric dietary advice from all manner of international agencies.

Growing food in a basket(case)

Do a little googling and you will find plenty of news stories over the past few years about China (and others) investing in Africa to grow food. At home, China is losing land to desertification and running out of water. It has also developed a taste for beef and now has over 80 million cattle (plus 20 million buffaloes) to feed on top of its half a billion pigs. What is the cause of so much of its desertification? Grazing, of course, with sheep being as effective as cattle.

But why Africa? How do you produce food in Africa? This is the continent with the worst food insecurity on the planet. A New York Timesarticle relates the astonishment of a botanist who was flabbergasted at Saudi plans to grow food in Africa, thinking that if Africa can’t feed itself, how can it feed foreign markets? Easy. With some exceptions the problems of food in Africa are cultural and financial, they are not technical. Africa is 3 times bigger than China with 300 million less people. Yes, it has some rather large desert regions (40 percentof the land area), and some poor soils, but also large areas of current and potential forest. In simple terms, if mother nature can produce a forest somewhere then a good farmer can grow food.

Foreign investors are demonstrating this in many countries in Africa. The Guinea Savannah mentioned in the NYT article above matches the vertically hatched area of the Nature paper quite well. This is land that can grow vast amounts of food but is currently set on fire in a massive cattle conflagration each year that produces nothing but ongoing boverty.

To be specific, Ethiopia, for example, claims (see above IPCC submission) about 73 million hectares of land suitable for farming but is using just 7 million. It has 3.7 million hectares suitable for irrigation and with adequate river water resources but has only 160,000 under irrigation.

Africa’s undernutrition problem, put simply, is that more than a few countries have a culture which prefers cattle and burning the shit out of the country to growing food.

Aid agencies … anyone for desert(ification)?

What is the role of aid agencies? Before proceeding, let me say that for many years I’ve been, and will continue to be, a regular donor to Oxfam. But the criticisms in this post must be addressed. Supporting disfunctional food cultures and policies isn’t aid, it is, at best, assisted suicide.

Part of the problem in dealing with Australian aid agencies is nutritional ignorance fanned by decades of meat industry lies couple with a deeply ingrained Australian BBQ culture. The irony of seeing the McGrath Foundation promoting the biggest source of bowel cancer in Australia, red meat, with BBQs outside supermarkets to raise funds to assist breast cancer victims is probably not uniquely Australian, but does illustrate the extent of the problem. Belief in the superiority of meat as the only real source of all the nutrients which matter is a myth that runs deeper in the Australian psyche than the Pope’s belief in God.

To illustrate, here is a 2010 ad from the Australia Day Council. It couldn’t have been more blatantly an ad for Meat and Livestock Australia if the latter had commissioned it from their ad agency. Note in particular the three meats: steak, sausages and lamb chops. There is no chicken … MLA is locked in a mortal battle with the chicken industry. Either I’m right about the ingrained nature of BBQ myths in Australia, particular among the those in positions of cultural influence, or there is serious corruption at the Australia Day Council.

But the king in the international spread of Boverty is not Australian, it is a US based group, Heifer International. This group runs, among other things, irrigated dairy projects in Ethiopia. A dairy industry, especially an irrigated dairy industry, is a brilliant way to fritter away scarce water resources and create a water crisis. New Scientist journalist Fred Pearce, in his book When the rivers run dry, wrote about the dairy driven plight of Gujarat in India. Pearce sketches the Gujarat irrigation treadmill nightmare as wells are driven ever deeper into a dropping water table to flood irrigate fodder fields for cattle. Again, the farmers involved may well profit, it is future food security that is being traded away. Where irrigation is river, rather than groundwater based, it is the opportunity for more productive use of water which is lost.

First world countries are not immune from dairy’s water hungry ways. In Australia, the dairy industry has been the biggest culprit in the over-allocation of Murray Darling Basin water. It is far and away the biggest user of irrigation water in Australia. At its peak in 2000/1 it dominated water use in the Murray Darling Basin using more than double the water of rice and 9 times more than fruit and vegetables combined. For all that water, the dairy industry in 2000/1 produced just 20 percent more calories than rice … with many of those calories being saturated fat which, in the developed world, is removed before sale … because it kills people. Some may argue that this is not an issue in parts of the world where diseases of poverty kill people before they get heart disease, but this isn’t accurate. The toll of ischemic heart disease is often high in developing countries. For example, the disability adjusted life years (DALY) lost rate due to heart disease in Sudan is four time higher than in Australia. Sudan can’t do the 40,000 major heart operations that Australia does annually to subsidise our livestock and junk food industries.

The revenue per million litres of that Murray Darling Basin dairy water was about 1/9 of that of water used to grow fruit, but with so much water being funnelled through the paddocks, it was still profitable … until the inevitable drought spoiled the party. Similarly, those Ethiopians involved in irrigated dairy production may be well be making good money, but regardless of the financial success of livestock aid projects in Africa, the long term impact of anything which serves to increase in the ratio of livestock to human biomass can only be to decrease food security for both humans and wildlife.

Of course it is true that understanding the root causes of a problem does not automatically provide solutions. Mapping realistic pathways to change a culture is tough and western countries have shown their own inadequacies in this regard by their inability to tackle the much simpler problem of obesity. We have been incapable of taking strong action against ingrained false and dysfunctional beliefs and against organisations who are perfectly happy to make people fat and unhealthy for a living (e.g., Hungry Jacks).

So let’s look at how Oxfam, Heifer International, World Vision, and other agencies who run livestock projects, directly contribute to African poverty.

None of the cattle owners in the study had enough land to meet the grazing requirements of their cattle, but local custom allows them to graze on anybody’s crop residues … without permission.

Residue grazing has many impacts.

It removes nutrients in the residues and uncovers the soil which maximises the further loss of topsoil and nutrients to wind and rain while the trampling ruins the soil structure. Yes indeed, soil has a structure and the physical structure effects everything from water flow and erosion rates to how nutrients find their way into roots.

The best you can hope for is that some of the nutrients may be returned as fertiliser. The key word here is some and may. Cattle dung from residue grazing can’t add nutrients to the soil that weren’t already in the residue and where dung is removed for fuel, the loss of nutrients is large.

It is taking farmers everywhere, not just in the developing world, quite some time to realise that bare fields are a recipe for long term agricultural decline, with ploughed bare fields being even worse.

Continuing with the Kenya grazing practices, … and again, the same will be true in many places. When cattle are grazing in and around crops and fences are largely non-existent, cattle need to be shepherded to stop them eating and trampling crops, this requires people power. An alternative control method when labour is short is to tether the cattle. This is perfect for concentrating and maximising the damage from cattle.

The low productivity of the soils was mentioned by the IFPRI author without apparently realising that she had described many of the processes that had produced that low productivity. The productivity of soils isn’t a given, it is a product of many things with more than a few being under our influence.

But cattle aren’t perfect. They will browse bushes but are more naturally grazers. If you want perfection in land degradation, you need to add an animal who can clean up any young shrubs and trees which the cattle hooves miss. You don’t want any vegetation to impede the winds in their efforts to blow away your topsoil. Goats are pretty well perfect for the job. The dynamic duo of cattle and goats will maximise the area left bare so that the wind and rain can strip topsoil to uncropped areas. Better still, if you have a local stream or river, the drifting soil from ground left bare by goats and cattle can silt it up for you. This is an added bonus in the raft of eco-system disservices provided by livestock.

Goat feeding for beginners

Goats are remarkable creatures, but frequently misunderstood. Their role as Oxfam gifts singles them out for particular attention. The capacity of goats to survive in harsh environments is achieved by pretty much the opposite of what most people believe. Goats don’t have low nutrient needs which can be met by any old plant matter. Assuming that you want a goat for milk and not just companionship and decoration, the standard veterinary advice on the minimal protein intake required for a 50 kilogram milk producing goat is 174 grams of protein per day. That’s enough protein to feed about 220 kilograms worth of people.

To get the required feed to enable lactation, assuming you aren’t buying any feed, that 50 kilogram milking goat needs to eat about 2 kilograms of dry matter per day. This is the average NPP (remember NPP from Part I? Net Primary Productivity, a fancy word for plant growth) of 5 square meters of Africa over an entire year. This means a single milking goat will consume the entire plant growth of 1825 square meters of land during a year. But goats have no interest in NPP maximisation. Confine a goat to exactly 1825 square meters (about 2 empty suburban blocks) and you won’t find it in the same state at the end of the year, with the goat having nicely harvested the annual growth. No. A goat won’t feed to maximise the area’s productivity, it will start with the new growing shoots, stems and leaves. This depresses NPP. In a sense, the goat will gradually eat its way down the food quality chain and a dust bowl will be the result.

African goat breeds will have parameters somewhat different from those I’ve cited, and averages must always be taken for what they are, but the picture is clear. If you want to establish a belt of trees to shelter your fields and possibly for harvest when mature, then a free roaming goat is your worst nightmare.

Many aid agencies offer donors the chance to donate animals to a poor African family and goats feature prominently. Oxfam and World Vision are just examples. There are now some 290 million goats in Africa along with a similar number of sheep. To the extent that aid agencies encourage livestock acquisition, they are damaging long term prospects for food security.

Miscellaneous Boverty impacts

This last section looks at a few issues that are boverty related in varying degrees.

Cooking the planet

Globally we use almost as much biomass (as wood) for for heating and cooking as we eat. It amounts to about 10 percent of the 12.1 billion tonnes harvested or grazed. Remember we eat about 12 percent.

Many of the world’s poor have no choice but to cook and heat with biomass. Some not-so-poor people do it by choice. Typically the biomass is wood, but for poor people it can also be dung or crop residues. Burning biomass produces smoke. Smoke is an all-natural product containing a dazzling array of all-natural harmful chemicals. A US EPA approved wood stove generates very little smoke, but the stoves of the developing world generate plenty and have a death toll of about 1.4 million people each year. The main victims are women and children who spend more time near cooking stoves. Many of the smoke related respiratory infections wouldn’t be deadly with basic antibiotics and reasonable medical care.

Burning dung or crop residues out of desperate need or ignorance is tragic. The best use for dung is as fertiliser, and the best use for crop residues is to leave them to protect the soil. Biochar technologies are unlikely to change this in the short to medium term. Biocharing residues extracts and binds more carbon, but the cost is leaving soil uncovered.

There have been a variety of recent initiatives to design and distribute more efficient biomass cookers, but the low energy density of dung makes complete combustion to minimise harmful emissions a particularly difficult design problem under the strict cost constraints (Prof. Kirk Smith, by email). The 3 billion people who cook with biomass desperately need better energy sources. They shouldn’t be burning animal dung or crop residues. Burning biomass of any kind in primitive stoves is thus both a significant health and greenhouse issue.

Ozone’s jekyll and hyde show

As the largest source of anthropogenic methane, livestock are partly responsible for another all-natural dangerous pollutant: ozone.

Ozone is a good guy up in the stratosphere where it protects us from UV radiation, but a bad guy at ground level. Spikes in ozone levels occur in polluted areas thanks to sunlight acting on chemicals called VOC (volatile organic compounds). VOCs are a broad class of chemicals, encompassing things as diverse as petrochemical pollution fumes and the most delicious of cooking smells. Unhappily modern living seems to create more VOCs like the former than the latter. The resulting ozone spikes cause increases in asthma, bronchitis and heart attacks … to name but a few.

Wildlife or cattle, choose one

In July 2009 a major study confirmed what some African wildlife experts had long suspected. Key species in Kenya had declined by some 40 percent over the past 30 years, both inside and adjacent to national parks. The causes: poaching, bush meat, habitat destruction and human encroachment.

Kenyan rangers recently ejected 10,000 cattle from Tsavo West park. Massive cattle tracks visible from the air also show that herders have been illegally driving their cattle into the heart of the Masai Mara National reserve.

The story in Africa has direct parallels with the history of livestock expansion in the US, Australia and Brazil. Australian pastoralists have long seen deforestation as a legitimate farming practice.

Desertification

In semi-arid areas of Africa and elsewhere grazing can accelerate desertification in various ways. Cattle eat a patch bare and trample it hard. This decreases the amount of water that enters the soil, instead it runs on to vegetated areas which increase in growth because of additional water. This focuses grazing on the patches of vegetation which remain. This creates a postive feedback and patchiness results. More generally, grazing changes surface reflectivity (albedo) which can act as a further positive feedback on a large scale. This has been found to change soil temperatures and rainfall in the African Sahel as well as India. Smaller impacts have been found in comparisons between areas differentially grazed along the US/Mexico border.

Cattle, goats and V8 utes

I began the first part of this post with an analogy about SUVs and their societal impacts. There is a related automotive analogy that probably has more explanatory value, particularly for Australian audiences. Visit any country town in Australia and you will see an impressive collection of utes, often with huge V8 engines. A ute is the Australian equivalent of a “pickup” in the US. A V8 ute earns its owner considerable prestige within their circle of peers, but absorbs petrol like a parched flood plain. Dollars which could go into education and high quality food for a family ends up vanishing into the ute for a tiny transportation payback.

So it is with livestock in Africa, sometimes aided and abetted by aid organisations trying to satisfy the dangerously dysfunctional aspirations of people with strong cultural bonds to cattle. This week’s Lancet editorial was too polite (or scared of legal consequences) to name the aid organisations it attacked, but it certainly spread plenty of shame. The various “Livestock for Africa” begging campaigns are excellent examples of what happens when aid agencies lose the plot.

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Appendices

Terminology: Grasslands and Savannas

In this article, I’ve used the terms grassland and savanna without paying any attention to the technical differences. Savannas are sprinkled with trees. The timing and amount of rainfall tends to be different also. Scientist have various sub-categories, some of which occur naturally. Elephants seem to be the only other species besides us which can make savannas. In some circumstances, cattle can destroy grasslands. Their preference for grasses allows woody vegetation to gain a hold … this is the start of reforestation. Without people or lightening to burn this, or enough active browsing, some kind of forest will probably reassert itself.

Digression on Protein

Livestock producers and advocates generally have such a profound ignorance of nutritional issues that they often talk as if meat and protein are synonomous while vegetable protein is an oxy-moron. A cursory check of the WHO Food Balance Database tells a different story. Meat in all its forms provides just 17 percent of global protein. Animal products in total, provide just 40 percent. Increasingly, the weapon of choice against life-threatening undernourishment in children is plumpy’nut. This is pretty much a vitamin and mineral fortified peanut butter which outperforms the older vitamin and mineral fortified milk-powder based F100 formula. A newer wheat based solid product, BP100, is also available.

Plumpy’nut is often described as a high protein high energy spread. It is described this way because the nutritionists involved know what they are talking about. They know that the protein requirements of people are very low, about 7 percent of calories. Plumpy’nut has about 10 percent of its calories as protein … which makes it high. But vague words like high and low can change meanings depending on the context. In the advertising jargon world of popular nutrition hype, this is a low protein food. For comparison, the CSIRO Total Wellbeing Diet recommends 30 percent of calories from protein and is based around a food, lean red meat, which typically has 80 percent of calories as protein. So in a typical western context it is quite misleading to call this food high protein. In common parlance, plumpy’nut should be described as a low protein, plant based, high energy, life saving food.

One notable advantage of both Plumpy’nut and BP100 over F100 is that F100 looks like milk formula. This can undermine efforts to have mothers breast feed instead of using infant formula.

Yams is pretty much a generic term in western countries, often meaning sweet potato (which aren’t really yams), but the various Dioscorea, true yams, typically have very low nutrient density, but a high ratio of nutrients to calories, particularly minerals like iron and zinc and protein. For example, some have more than half their calories as protein.

Digression on Fish

For those who have swallowed, hook line and sinker, the fish industry propaganda that fish is brain food or a vital global source of protein … both are excellent examples of the old maxim, if you must lie, tell a whopper and tell it often.

Globally, fish and seafood is about 1 percent of calories and included in the 17 percent provided from animal sources in part 1 of this post. We are, in effect, trashing the oceans for an entirely superfluous food. The campaign to persuade people to eat fish as brain food is simply junk science gone crazy. The Japanese have a per-capita fish consumption 5 times that of the Australians, Germans, Chinese or Americans. Has all that fish made them smarter? The whole notion of brain food is based on deeply flawed reasoning. One of the world’s foremost experts on IQ, James Flynn recently wrote an article Requiem for nutrition as the cause of IQ gains. The name says it all.

Industrial fishing hauls vast amounts of sea life out of the ocean and extracts the small amount which is valuable. The rest is called bycatch. Jonathan Saffran Foer’s interesting new book Eating Animals paints an accurate picture of the mind numbing (usually ignorant) destructiveness of almost all people who eat fish: If a plate of sushi was served with all the bycatch associated with its production, then the plate could be around 5 feet wide. In some cases, seafood bycatch also includes people. Many of the 146,000 people killed by cyclone Nargis in Burma in 2008 died because the mangroves which used to protect the coastline had been cleared for prawn farms.

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28 Comments

I think hoofed grazing animals will have some role to play even if we switch from meat to plant protein. Using these animals to reduce fire hazard near suburbs rather than burning off removes the risk of asthma to kids or of burns getting out of control. Sporadic grazing can knock down woody weeds such as blackberry, briar, willow and hawthorn. The trick is to move the animals before they inhibit growth of a subsequent crop. The manure may mean less synthetic nitrogen applications.

Another virtue of animals as a food source is they are self propelled. To some extent the food source goes to the water not vice versa as in plants. In future animals should be farmed sparingly. A hamburger for example could be 10% animal products and the rest plant based. Similar protein but lower fat and cholesterol. Ditto plant boosted dairy eg more pectin less milk fat but some don’t care for the taste. Meat cravers could always switch to farmed fish.

I think we will end up eating more spuds less grain based starch when there is no tractor diesel or synthetic urea for the wheatbelt. We can grow the spuds nearby in our own wastes. Ah the future.

First I would like to thank the author of this post for a very informative treatment of the subject. The line: “With some exceptions the problems of food in Africa are cultural and financial, they are not technical,” was as true forty years ago, when I was roundly criticized in college for saying so, as it is now. Unfortunately it would seem that it is still a contentious idea today.

However while aid-programs have helped amplify the impact of some poor local practices, notably by mechanizing the drilling of wells, removing the limits that water availability put on the number of animals that an area could support, we cannot discount the role of cotton as well.

Cotton has come to symbolize ‘development’ in a number of African nations. Thus we have the spectacle of some countries’ economies dependent on the cultivation of cotton, and the country’s food supplies dependent on the money from the sale of cotton to offset the arable land that was taken out of food production and shifted to cotton. Of course when world cotton prices collapse, and food prices soar, as they have of late, hunger follows.

My understanding is that rainfall patterns and amounts largely determine the nature of climax vegetation. The first map in this post is interesting in purporting to show which areas are held as savanna by cattle and goats that, naturally, would have a forest climax. I have a few questions relating to this.
1) Can the observation be validated by study of the past? In other words, were the areas identified as being potential forest ever actual forest at times when the climate was similar to that of today?
2) If not, presumably the effects of lightning, elephants, wild ungulates or even termites (non anthropogenic agents) were responsible for the so-called sub climax vegetation?
3) Is it possible that the potentially forested areas that you identify would be “anthropogenic forest “, created only because man has wiped out most of the natural megafauna?

I am sure you are aware of (I think) Australian research that has demonstrated that that ruminant grazing can be managed in such a way as to restore the soil structure and productivity of degraded grasslands. I fully accept that, in much of Africa, grazing patterns are harmful and domestic livestock numbers are too high. In other words, the human population has reached levels that exceed the carrying capacity of land that is farmed in the traditional manner. However, it doesn’t follow that it is necessarily simple to switch to, for example, root vegetable production as an escape from hunger.

The way in which protein requirements are dealt with in this post is somewhat naive. It is true that vegetable material can provide most (even all) of one’s protein requirements, particularly when supplemented with synthetic limiting essential amino acids. However, without such supplementation, one would need to ingest far more than 7% of one’s calories as protein for an adult maintenance diet. Even with supplementation, 7% would not meet the needs of growth, pregnancy or lactation.

The vegetative parts of plants are high in fibre and not readily digested by non ruminant animals such as humans. We need low fibre diets (seeds, roots, tubers) plus some animal protein to compensate for the essential amino acids that are limiting or absent in them. Admittedly, we don’t need as much animal protein (meat/dairy products) as Westerners typically consume. In a free society, we eat what we like if we can readily afford to do so.

Ruminants (among mammals) are uniquely equipped to convert high fibre biomass into food material suitable for non ruminant animals such as ourselves (although equids don’t make a bad fist of it either and aren’t such significant methane producers).

Is it the author’s suggestion that Africa should become largely forested but that large tracts of savanna should also be rendered suitable for arable production for human food? if so, there are implications involving water availability, irrigation, plant protection and many others.

I’ve heard the claim that ‘trees bring rain’, but without references to back it up. If so then allowing some grassland to turn into forest might result in some desert turning into grassland. Is there anything to that claim?

Douglas: Taking the last point first. There will be competition in Africa between
goals of food and forests. Food will win. Some of the best soils are also
under existing forests so a kind of swap would be good. The sad part is that
some Western aid groups are perpetuating the myth that livestock equals food,
which allows overseas interests to come in, grow the food and export it. In
one sense as long as somebody who needs it eats it, then this is good. But
hungry Africans might get pissed at seeing food grown locally being
exported to feed people in China.

I refer you to the Nature paper for detail on your first issues. They used
data from 854 sites over at least 20 years
and (amazingly) didn’t find herbivory was critical for
maintaining the savannas. It was fire. Deliberately lit fires.

As for my naive treatment of protein requirements. You’ll have to take
that up with the National Health and Medical Research Council and its
Nutrient reference values (http://www.nrv.gov.au/). They don’t
think anybody needs animal protein … there are good reasons why
breast is best, but it doesn’t have to do with protein … infants grow
perfectly well on soy formula. NMHRC give different
requirements for iron intake in vegetarians and meat eaters, because of
the lower absorption of iron, but they have no such different requirements
for protein. Even during lactation, a women’s protein intake requirement
is about 1g per kg of body weight (less than a third of what is required
for a goat!). For a 60kg woman, this is 240 calories of protein. About
10% of intake depending on activity level, so yes 7% didn’t
cover lactation, but 10% isn’t “far more” in my view.
The issue of limiting amino acids is a theoretical construct of little
applicability with people eating real foods in reasonable quantity.
Consider Nigeria, there are quite
high (20% from memory) stunting levels, but this also shows that
80% of people, almost all of whom get little or no animal protein on
a daily basis are fine, and given the 8% undernourishment level, its
still pretty clear that this issue is one of food quantity not a lack
of animal protein. The issue of nutrition in such places is intertwined
with other issues like parasite loads, clean water and the like. There
are all kinds of physiological stressors in addition to not enough food.
The WHO-DALY (disability adjusted years of life lost) figure for
protein-energy malnutrition (huge battles
were fought over this term in the 1970s … ) in Nigeria is 476, for
infectious/parasitic disease, the DALY figure is ~18,000 (which
includes AIDs at ~4,000) … it’s about half the road traffic DALY figure of 861.

Lastly, there are plenty of ways of rehabilitating degraded grasslands.
It’s usually as simple is removing the livestock. Plenty of our grasslands,
just like those of Africa will reforest if given a chance. Certainly some
farmers run better grazing operations than others. But straight grazing
isn’t very productive, which is why so many people send animals to
fatten on grain before slaughter. And that’s grain we can no longer export
to people who need it.

The other question of course Geoff is the micronutrient B12 (cyanocobalamin) which is more bioavailable in animal sources. Luckily, RDA is only about 12mcg, and it can be sourced from non animal stock — (mushrooms come to mind here) and vegetables grown in organic manure (if you don’t quite wash them) and there are of course ways of synthesising it, but even so …

Ewen: Full marks for remembering 1987 lectures! I was working from the
latest NHMRC document (which I linked to) … 2005. I could spend a lot
of words defending much lower protein requirements. WHO reports contain
the following recommendations in grams per kg of body weight: 1957 0.88,
1965 1.18, 1973 0.82 and 1985 0.88 (back to 1957 level!). All these numbers
are for young adult males and contain an “allowance for those on the
poorest diet”. Protein recommendations
are somewhat political and historically vary according
to the size of the animal industries in the country of origin :)

As for B12. The US Institutute of Medicine recommends supplements
for anybody over 50 … because the supplements are MORE bioavailable
than that in meat. As you age reductions in gastric acid (and
other factors) typically lead
to poor absorption of foodbound b12, but not the crystalline stuff in
supplements.http://www.nap.edu/catalog.php?record_id=6015

Meat is a very expensive way to get B12 … . And if people in animal-rich
countries like the US and Australia still need supplements (plenty
of foods have B12 added to them, and it’s not for us vegans, we don’t
have that much market power!), then providing animal based sources
in developing countries is grossly inefficient. I’ve been trying to
find the root source of b12 used in Australia, and it
seems to come mainly from Chinese pharmaceutical makers. The stuff
is very cheap. Farmers use it for sheep and cattle grazing cobalt deficient
pastures … so you might as well eat it direct from the factory and
cut out the middleman.

Ewen: FWIW, B12 deficiency is a cause of heart disease. The pathway
is a little complex but reasonably well understood. Vegans often
resist taking B12 supplements as unnatural, so while their heart
disease rates are lower than meat eaters, they are (in the biggest studies) not
as far below as vegetarians.

With a hat tip to “flxible” at RC 4 February 2010 at 2:26 PM
these 2 links are worth looking at. The economic pressure is to replace that burning with mechanized agriculture, which will waste topsoil more rapidly than field burning:

Thanks for your reply. I looked at the Nature link to which you referred. Not being a subscriber, I only had access to the abstract. This stated that savannas were unstable when MAP exceeded of 650mm and depended on fires and herbivory to prevent canopy closure. In other words, the unimportance of herbivory to which you allude was not mentioned in the paper’s summary.

You refer to a 20 year study in which fire (deliberately set) was important in savanna maintenance but not herbivory. Having worked for brief periods in East Africa both on the detrimental effects of elephants on established forests and on increasing cattle productivity, I have a few comments and observations that may be relevant.
1) Elephants are generally accepted as being important in preventing grassland from being engulfed entirely by trees and, in fact, being capable of clearing open spaces in closed canopy areas. I would imagine that wild browsers (eg black rhino, kudu, gerenuk, giraffe etc etc) might have similar effects on woody vegetation that you describe for goats.
2) Depending upon the sizes of the study areas to which you referred, perhaps 20 years isn’t long enough to enable the dismissal of the importance of lightning. In any event, my point about “anthropogenic forest” was not addressed.
3) Cattle productivity in my study area was very low without “tweaking”, mainly because beasts couldn’t be finished for five or six years. They gained weight towards the end of rainy seasons and at the start of the following dry season only to lose about 80% of it during the rest of the dry season and start of the next rains. (Tropical grass is very rapidly maturing and its digestibility level falls much quicker than that of temperate grass due to lignification. High lignin grass cannot be eaten in the same quantity as younger grass because the ruminant takes longer to process it. It is ironic , in fact, that a ruminant’s appetite drops at the very time it needs to eat more to compensate for the falling energy density of its diet. Zebras, though not digesting fibre as efficiently, compensate by upping their appetites in compensation for falling D values. In extreme droughts, therefore, they tend to survive while ruminants may die).
4) On the ranch I was involved with, dams were constructed to impound surplus rainy season water for irrigation of less than 1% of the area. On this, maize was grown, allowing cattle to finish at a weight and in a condition that would not otherwise have been achieved for several more years. There was also sufficient maize for the farm labourers. The most economic approach appeared to be use the open range for store cattle production and wildlife (with tourist income potential) and the productive, irrigated bit for finishing only. This allowed for much greater meat production than could otherwise have been achieved. The point I am trying to make is that the critical factor is the ready availability of water. One couldn’t have used the majority of the ranch for arable production but it produced cattle and only a small proportion of the diet of these cattle was competing directly with humans for food – that used in the short finishing period.
5) We also found trace mineral deficiencies were quite common (eg selenium) which severely limited grazing livestock productivity but which were relatively easily and cheaply rectified.
6) One further comment on protein. For ruminants, one normally talks of crude protein in relation to dietary requirements and crude protein can include non protein nitrogen (useless for people) but as good as true protein for 50% of the ruminant’s protein needs for maintenance.

Hank Roberts gave a link which touched on the scramble for arable land in Africa by outsiders. There is no doubt huge potential to produce more food there. Not all methods applied are necessarily unsustainable but there are no doubt plenty of examples of aquifer mining and other short term expedients. In terms of greenhouse gas output, I would be interested in the relative effects of ripping up savanna and consequent soil carbon loss with leaving it for cattle and wildlife to graze. I would also be interested in the potential for slow pyrolysis and carbon sequestration in the organic carbon- poor soils in many parts of Africa. The forests that you would like to regenerate might have greater utility if they could, in part, contibute to soil improvement elsewhere.

Douglas: send me your email and I’ll send you the paper … geoffrey.russell [at] gmail.com … I’ll respond later to the various interesting points you have raised.

Hank: If we manage to adapt to changing water regimes, peak oil and overpopulation driven conflicts … topsoil loss may well be the final horseman of
the apocalypse. But the bottom line is simple. Crops feed the planet, 83% of
global calories. Less livestock means we need less crops (particularly pigs
and chickens). The most effective way to reduce the requirement for cropping is
to reduce the populations that eat the crops … pigs, chickens, cattle, people. I favour prioritising the first 3.

Douglas: I’ll respond fully later, but one point demands immediate attention. There was sufficient maize for the farm labourers. Why not
feed them beef? Because it costs far too much to produce to sell to poor
people.

Great stuff as usual. Having done a lot of aid work in Africa personally, I can vouch for how bad the situation has gotten in places. All kinds of terrible social mores lead to sub-optimal methods of food production, and environmental destruction. The Africans I met LOVED meat! The idea that it was keeping them in poverty never really occurred to them. The vegetable farmers I met in Namibia were white and rich, from using 0.1% of the land that would be used to produce the same food using ranches. What it requires most is skills transfer and capability building (mechanics, agriculture, etc). If the aid agencies focused on that, they would gradually be able to pull themselves up by their bootstraps to better lives for all.

Thank you Mr. Russell for a very thought provoking article. My mind is spinning with the implications.

Some things that really stuck out for me include:
1. 90 % of fires are anthropogenic and 2/3 of those are livestock-related. Couple this with the new push to reduce black carbon emissions due to the belief black carbon is a leading (if not the leading) cause of rapid glacial melt, and the estimate that 40 to 50 percent of black carbon comes from forest fires and we can guestimate that livestock are the single largest source of black carbon (with a global warming potential of 4470 times that of CO2) — making livestock a much bigger cause of climate change than previous estimates.

2. I recently read that when many African nations reported their emissions to the IPCC, they didn’t report much, and I did not see them reporting large amounts of methane emissions. This indicates there is a lot more methane out there warming the planet — again making livestock a much bigger cause in climate change than previous estimates.

3. Groups like the Arctic Council is calling for a reduction of methane, tropospheric ozone and black carbon as a rapid way to reduce Arctic ice melt. They state the best way to reduce ozone is to reduce methane, and that any methane reductions will help the Arctic. they also say that regional black carbon reductions (from industry in the northern hemisphere and diesel), while others call for black carbon reductions from people in india burning biomass for fuel to halt Himalayan ice melt. We already know livestock are the single largest source of anthropogenic methane from Livestock’s Long Shadow, and with these links to forest fires and black carbon — and methane’s role in creating ozone — it means the best way to bring about to bring about rapid planetary cooling and halt (or slowed rate) of glacial ice melt. (Brazilian scientists have found that there is black carbon in Antarctica and 30% comes from Africa, 50% from biomass burning in South America, 20% from industrial causes in South America — indicating that most of black carbon in Antarctica is from the livestock industry).

4. All those African leaders so upset in Copenhagen, claiming that setting a goal of keeping emissions reductions to under 2C was tantamount to a death sentence for Africa can now take control of their own destiny — not rely on the worlds largest developing nations — to ensure food security, water security, national and regional security and create planetary cooling by ending livestock production, allowing the forests to come back and farming plant-based foods.

Bravo! Great research. I look forward to more posts expanding my understanding of the role livestock play in climate change!

Jim Baerg: “trees bring rain” … Tim Lenton’s tipping point paper lists Amazon dieback as a major risk in a changing climate. If “trees bring rain” was
a law of nature, then once you had plenty of trees, they would in effect
water themselves for ever. The details will be in the modelling and
are probably much more complex than the simple aphorism.

DV82XL: Read “When rivers run dry” for some cotton horror stories from Fred
Pearce. My link above on the Murray Darling has dairy use
at 4200 giga litres in 2001 with cotton at 2800 giga litres and rice at 1800
giga litres … but a zillion letters to the editor have complained about
rice in terms of loathing and disgust over the past few years and I think
I’m the only person who has mentioned dairy and such letters are
rarely published. I reckon its a subtle form of Aussie racism. But whether its
rice, cotton, dairy or watermelons, it can cause an over allocation of water
when its political power overwhelms sensible decision making. The
dairy industry has huge power precisely because it is composed of
lots of smallish farms who all vote in country electorates and because
it has bought a lot of research results over the years … see Marion
Nestle’s “Food Politics” for US examples.

Douglas: 1) you have the Nature paper now. If you think I’ve misrepresented
it, then let us all know, but I’ve tried to represent it accurately.
2) see 1)
3) There are 2 basic ways to think about food.

A) Maximise food production from a given region/country.
B) Minimise land required to feed a given population.

A) calls for maximum appropriation of land to human use. Any land not
used for us is “wasted” unless we dedicate it as a reserve. If it doesn’t
have some iconic species in it to give it that special status, then it is
fair game (an appropriate expression). B) doesn’t accept, for example,
trucking thousands of cattle into the Lake Eyre basin to take advantage
of rare big rain events which would other wise be “wasted” on waterbirds,
reptiles, and dare I say it … plants.

Your comments on non-protein nitrogen are interesting and illustrative.
I’m not sure what you are talking about, but in feedlots this is typically
thinks like cow and chicken shit. Feed this to ruminants and the gut
flora make the N into protein. I say the best use for cow and
chicken shit is as fertiliser for plants to make into protein.

It is definitely my suggestion that Africans get fed and this isn’t
happening now, despite abundant livestock … it isn’t happening
because of the livestock. So yes convert savanna to farmland where
possible, reforest anything you don’t need. The goal is to feed people
without deforesting what’s left of the jungle. The other requirement is
cheap energy to replace charcoal, wood and dung for cooking … nuclear
batteries look the best options. Mass produced 10MW batteries buried
all over Africa to take the pressure off the remaining forests. This is
our payment to them to keep those jungles!

I have now had time to read the full Nature article which you very kindly e-mailed to me.

You asked me to report on whether I think you have misrepresented the findings. By and large, I don’t think you have. However, the authors’ conclusions that fire return intervals of less than 10.5 years appeared to be much more important than herbivory in their study areas should be qualified (and the authors do, indeed qualify it). I don’t think you did but you might find this nitpicking. Only 21% of studied sites provided data on biomass of herbivores. These ranged from 0-80kg/ha. No information was given as to whether this was average seasonal stocking density, a maximum at a favourable time of year or a snapshot at a single time. Further, no information was given as to how the biomass was proportioned between wild and domesticated or between browsers and grazers.

A maximum density of 80kg/ha is, of course, low for managed livestock agriculture in areas that have good soil and adequate rain. In more arid areas with poorish soil, the carrying capacity could be much lower than the 80kg/ha. This would best be measured in areas where there were no domesticated stock, no hunting and undisturbed wild herbivores (possibly, national park areas). Ideally, of course, predator elimination might be needed. To this extent, it might be better to look at large ranches with mixed wild and domesticated herbivores but few large predators and, on which, supplementary feeding was not practised unless accounted for by adjusting natural carrying capacity downwards.

In other words, I don’t think the paper, of itself. provided answers to the questions I posed. If I knew what the natural herbivore carrying capacities were relative to those recorded in the study sites, it might have helped – but I don’t. Also, I don’t know how often lightning would strike and start fires. However, I accept that much African savanna might be converted to woodland if one wiped out the wild herbivores, didn’t stock it with domesticated stock and didn’t choose to start fires on it (hoping for the best on the subject of lightning). Anyway, I am not sure that increasing woodland would necessarily be desirable and am not convinced that it would feed more people, help the normally present wildlife or, except in the short term, reduce global CO2 emissions. You could, of course, counter by extolling the potential virtues of biochar sequestration and bio-oil combustion to replace charcoal burning.

In presenting the advantages of eating more vegetables and less meat/dairy, particularly in savanna-type areas, you could be over-simplifying matters. Suppose that ,maybe, 5% of the savanna could be used for arable but not the rest (due to water restrictions) and suppose that all that arable production went to people. Are you sure it would provide more human food than if 95% of the savanna were used for grazing and 5% used for supplementing the grazing animals. I haven’t attempted this calculation myself so it’s not a trick. In fact, my personal preference might be to leave the 95% for wildlife and exploit tourism (including controlled hunting) but this would depend upon a continuing stream of affluent trippers burning up fossil fuels with their flights. It would also directly replace domesticated ruminants belching out methane with wild ruminants doing the same.

I agree that many Africans are keeping unsustainable numbers of livestock on the areas they have available to them, given water constraints. (Apparently, the same could be happening in the Murray Darling basin). However, it remains the case in Africa that cattle and goats are not, by and large, competitors with arable but, rather, with wildlife.

The only way of turning significant amounts of unstable savanna into productive arable is to import water (from underground or from rivers) and fertilisers made from fossil fuels. Carrying capacity of humans can be greatly increased by use of said fossil fuels and this explains why the global human population is already greatly exceeding natural carrying capacity and will crash unless alternative forms of affordable energy are made available to replace fossil fuels when they run out. An attempt to revert to organic (sustainable?) farming will create the crash even before the fossil fuels run out.

It is quite true that a vegetarian approach to human nutrition requires less inputs than an omnivorous one. However, it is a false step to suppose that, if those who can currently afford meat became vegetarian, there would be more food for the poor. It costs money to produce food and, if the poor had it, they wouldn’t be hungry. The wealthy could (and do) buy food for the poor which tends to beget even more hungry poor. It may be possible to encourage the poor to use their resources more efficiently but efforts to do so are not always successful, hampered as they may be by poor governance, corruption and, possibly, inappropriate advice. In fact, agricultural infrastructure has tended to collapse consequent to the end of colonialism and the granting of independence.

Finally, I would go along with the potential for nuclear batteries but where do I get one and how much do they cost? Where can I go to see one working?

Douglas: How much of the guinea savannas would actually revert to
forest without fire and herbivory is a tough ask, but that Nature paper
had plenty of authors and the map was their best estimate with fire being
a bigger driver than herbivory in keeping the savannas. 5 percent arable?
In Australia we crop 24 million hectares and graze 400 million. The
cropping produces 5-15 times more food than the grazing. In fact if I had
accurate data to separate out the factory farmed from the grazed meat/dairy
production, the ratio would be even higher. There are indeed many
problems in changing diets whether here or in Africa, but the first
step is accuracy and honesty … about both the health and environmental
impacts. Our meat industry tells lies constantly
and these lies
are recycled on a daily basis, they infuse advertising, media and our
entire culture. They lie about health issues, they lie about cruelty, they lie
about environmental issues.

There are plenty of comments I haven’t addressed, thanks to everybody
for their attention. I’ve got some deadlines looming and some
personal matters to deal with so may not get to all the issues
for a while … keep watching your google reader (or other news source).

Retention of crop residues on soils, including the biomass produced from cover crops, is essential to numerous ecosystem services such as carbon sequestration, conservation of soil and water, and high use-efficiency of inputs for increasing and sustaining agronomic productivity. The agrarian stagnation and perpetual food deficit in sub-Saharan Africa is attributed to severe soil degradation (1, 2), caused by extractive farming practices that involve continuous removal of crop residues for use as traditional biofuels and cattle feed. This has created a negative nutrient budget. Soils are a source of greenhouse gases (CO2, CH4, and N2O) when prone to accelerated erosion and when under management that creates negative carbon and nutrient budgets. Crop residues and other biosolids are essential to maintain activity and species diversity of soil biota (micro- and macroorganisms) and to improve soil structure and tilth (3–5). Indiscriminate removal of crop residues and harvesting of biomass from cropland soils is supported neither by science nor by conventional wisdom.

Rattan Lal, and David Pimentel

This weeks Science has a stunningly misleading piece from the Livestock
advocacy and research centre (ILRI) which shows how little many top livestock scientists know about soil science.

Here (in full) is a highlighted box highlighting the lack of soil
science knowledge by the authors:

” Box 1. Enhancing livestock productivity through improved dual-purpose crops.
In developing countries, some crops like maize, wheat, sorghum, and millet are dual purpose:
Their grain provides food for humans and their residues are used as feed for livestock. Traditionally
these crops have been bred to improve grain yield and drought and pest resistance.
However, in the past decade it has been recognized that farmers in mixed crop-livestock systems
value the crop residues sometimes as much as the grain owing to their importance as a feed for
livestock, particularly in the dry season (29). Breeding programs for these crops are increasingly
being adapted to include breeding for residue quality without compromising the original objectives
associated with increasing grain yield.
In India, where the demand for crop residues as feed is very high, improved dual-purpose
varieties of sorghum and millet have had significant impacts on the productivity and efficiency of
crop-dairy systems. Small-holders have been able to increase the milk production of buffalos and
cows by up to 50% while at the same time obtaining the same grain output from their crops. This
has increased the demand for dual-purpose crops with relatively high-quality crop residues, and
burgeoning fodder markets have developed around cities like Hyderabad (29).

It should also be noted that the very first statement in the article is either
plain false or highly misleading.

Farmers in mixed crop-livestock systems produce about half of the world’s food. The implication that the livestock in these systems
is a sizeable part of “half the world’s food” is false. With livestock globally
providing 17% of calories and with many of these calories coming from
factory farms, so the implication is false. Much of the potential food output
of mixed crop-livestock systems will be being lost precisely because of
the deleterious impacts of the livestock on soil due to the consumption
of not only crop residues but other biomass and crops themselves. Most
crop residues are so low in nitrogen that they can’t contribute much,
if anything, to actual liveweight growth in the livestock. The cost of
residue grazing is high and any benefits small. The animals will require
additional good quality feed.

The article used by Herrero et al to support their claims of the
value of residues for livestock deals with only one kind
of residue (sorghum) and states clearly:The crude protein
contents of all [sorghum] stover types were well below 7.5% (Table 2),
the level widely considered as the minimum requirement
for rumen microbes to efficiently digest the feed.

The measured the sorghum stover (residue) crude protein content
was between 2.9 and 4.9 %. Fascinatingly the 2.9% stuff was
fetching the highest price!

Geoff: forgive this post. I mean to reread this article carefully but I have another question which I recall you commenting upon at some point.

when we talk here about nuclear power providing desalinated water, are we talking about drinking water primarily? in other words, I recall you suggesting that desal could not come close to dealing with the freshwater deficit faced by agriculture.

Short question, long answer. Short answer is ask a farmer how much
water they use and they’ll tell you how much they are supposed to
have used. Ask them how many hectares are being used for
what and then multiply by appropriate figure and you get another
answer. Then go for a boating trip along the Murray and look
for pipes without meters on them … are you getting the picture?

In answer to your question. The Adelaide desal plant will
produce 50-100 giga litres (I’ve seen both numbers). Dairy on
the Murray Darling Basin at its high point was pulling 4200 giga litres.
When water got short, the first people to stop planting was the
cotton and rice. They just didn’t plant, but cattle act like
a permanent planting … eventually they have downsized the herds
but it took quite some time.

Fruit and veg in the MDB was almost 500 giga litres, so nuclear desal
might be feasible for some things if the price and location is right.

Ideally I’d see cities changing. High density around veggie gardens
and fruit trees. I found a great little house at St Peters in Adelaide
recently … tiny front yard with 14 fruit trees … all planted close and
pruned to fit. Cities can produce plenty of food if attitudes can
be changed. Do the maths … think what you can produce from
a square metre (assuming water) during a year: tomatoes, spinach,
capsicum, etc, etc, Or use that metre to grow grain for chooks to lay
eggs. How many eggs do you get from a square metre over the
course of a year? … 1 (or up to 3 with high yield irrigated wheat).
Normal chook feed isn’t just grain … chooks (but not people) need
more protein than that, so chook feed is fortified with various high
protein meals and vitamins and minerals.

The blanket condemnation of grazing of crop residues is misleading. Many (or most) crop residues have very high carbon:nitrogen ratios because the plants have plundered the leaves and stems of protein and energy to produce the seed that we crop.

Excess carbon:nitrogen ratios make existing soil nitrogen much less available.

Grazing animals metabolise a large amount of the carbon while redepositing the nitrogen as urine and dung. Overgrazing is not an inevitable consequence.

An alternative way to reduce the carbon level might be to burn the residue but that destroy the nitrogenous compounds as well, leaving only the minerals. This is needed in regenerating Australian native woodland but is wasteful in most agricultural systems.

You could compost the crop residues but would have to factor in the energy required to harvest the residues, turn the heaps regularly and redistribute the finished compost over the land. Grazing would seem to be far more energetically efficient in most circumstances.

Comparing simple tonnages of meat and potatoes is a little misleading as to their respective nutritive values.